Intensity view add

Problem noticed during Montpellier workshop.
To test the PR.
 * Open an image with several z-section or timepoints.
 * Open the measurement tool
 * Draw a line and propagate it across z or t.
 * Select the shape
 * Go to "Intensity Results Tab" and add the selected shape
 * When the results of the shapes composing the ROI  are displayed in the table 
 * scroll to a new plane where the shape has been propagated. Check that the results of the shapes composing the RO are not added again to the table.
 * Draw another line. Save. Select and Add it. Make sure that only rows corresponding to the new line are added